1. Field of the Invention
The present invention relates generally to identification means having diffraction gratings and magnetic strips disposed thereon provided for security and authentication and, more particularly, but not by way of limitation, to novel method and apparatus for reading diffraction gratings on such an identification means when the magnetic strip thereon has been deGaussed.
2. Background Art
In the parents of the present application, and particularly in Ser. No. 07/921,460, there is described method and apparatus for reading a compound diffraction grating and an associated magnetic strip. Such optical images and magnetic strips are provided on identification means, such as credit cards, to assist in authentication of the identification means and to prevent or deter forgery of such identification means.
While the inventions described in the above-referenced applications provide a high level of security, a problem exists when the magnetic strip has become totally or partially deGaussed, either intentionally or accidentally. In such cases, when a deGaussed credit card is presented for a purchase, for example, the credit card will be rejected by the local authentication reader and the clerk may simply enter the identification number that is printed or embossed on the card without the authenticity of the card being verified by the local reader. Unscrupulous persons knowing of this possibility may intentionally degauss an invalid or forged credit card in the hope that the clerk may follow the above procedure.
Accordingly, it is a principal object of the present invention to provide method and apparatus for reading diffraction gratings on identification means when the magnetic strip thereon has been deGaussed.
It is a further object of the invention to provide such method and apparatus that are easily and economically employed.
Other objects of the present invention, as well as particular features, elements, and advantages thereof, will be elucidated in, or be apparent from, the following description and the accompanying drawing figures.